Various energy absorbing devices are used to dissipate kinetic energy as a result of an impact or other sudden forces. Such energy absorbing devices typically use methods such as hysteresis of a structural member, such as compression or stretching of rubber, bending of steel springs, cold-working of metal wire, or twisting of torsion bars; fluid friction, such as the flow of fluid through a narrow orifice; compression of a gas, such as a pneumatic shock absorber; controlled textile failure, such as ripping of stitching; and the like.
However, these devices and methods typically cannot match the amount of specific energy (i.e., energy per unit of mass) found in the controlled crushing of a composite tube. Further, these devices and methods are designed to absorb energy in only one direction, either in the tension direction or the compression direction.
Accordingly, those skilled in the art continue with research and development efforts in the field of energy absorbing devices to dissipate kinetic energy in response to a load or impact force.